The present invention relates to the field of leads for correcting arrhythmias of the heart. More particularly, this invention relates to leads for pacing and/or sensing the heart from the coronary vasculature.
A cardiac pacing system includes a battery powered pulse generator and one or more leads for delivering pulses to the heart. Current pulse generators include electronic circuitry for determining the nature of an irregular rhythm, commonly referred to as arrhythmia, and for timing the delivery of a pulse for a particular purpose. The pulse generator is typically implanted into a subcutaneous pocket made in the wall of the chest. Insulated wires called leads attached to the pulse generator are routed subcutaneously from the pocket to the shoulder or neck where the leads enter a major vein, usually the subclavian vein. The leads are then routed into the site of pacing, usually a chamber of the heart. The leads are electrically connected to the pulse generators on one end and are electrically connected to the heart on the other end. Electrodes on the leads provide the electrical connection of the lead to the heart. The leads deliver the electrical discharges from the pulse generator to the heart.
The electrodes are typically arranged on a lead body in two ways or categories. A pair of electrodes which form a single electrical circuit (i.e., one electrode is positive and one electrode is negative) positioned within the heart is a bipolar arrangement. The bipolar arrangement of electrodes requires two insulated wires positioned within the lead. When one electrode is positioned in or about the heart on a lead and represents one pole and the other electrode representing the other pole is the pulse generator, this arrangement is known as a unipolar arrangement. The unipolar arrangement of electrodes requires one insulated wire positioned within the lead.
Some patients require a pacing system having multiple sites in one chamber of the heart for detecting and correcting an abnormal heartbeat. In the past, a common practice for a patient requiring multi-site pacing within one or more chambers of the heart, would be to provide two separate and different leads attached to the particular chamber of the heart. One lead would be implanted at one site in the chamber. Another lead would be implanted at another site in the same chamber, or another chamber. Typically, the single chamber of the heart receiving multi-site pacing would be the right atrium.
Having two separate leads is undesirable for many reasons. Among these are the complexity of and time required for the implantation procedure for implanting two leads as compared to that of the procedure for implanting one lead. In addition, two leads may mechanically interact with one another after implantation which can result in dislodgement of one or both of the leads. In vivo mechanical interaction of the leads may also cause abrasion of the insulative layer along the lead which can result in electrical failure of one or both of the leads. Another problem is that as more leads are implanted in the heart, the ability to add leads is reduced. If the patient""s condition changes over time, the ability to add leads is restricted. Two separate leads also increase the risk of infection and may result in additional health care costs associated with re-implantation and follow-up.
It is well understood that the heart functions with two sides. The right side of the heart receives blood from the body and pumps it into the lungs to exchange gases. The left side of the heart receives the oxygenated blood from the heart and pumps it to the brain and throughout the body. As currently practiced, endocardial pacing and defibrillation leads are positioned within the right chambers of the heart. A major reason that this is typically practiced is that the risk of severe cerebral accidents during endocardial, left heart procedures is greater than that encountered during endocardial right side heart procedures. Although it is safer for the patient to position leads within the right heart, numerous difficulties are encountered when it is desired to sense and pace the left heart endocardially.
There is a need for an endocardial lead that can reliably perform pacing and sensing of the heart without being placed in the left side of the heart.
A lead is provided which includes a lead body adapted to carry signals to and from a heart, where the lead body has a proximal portion and a distal portion. The lead further includes a connector located at a proximal end of the lead. The lead is adapted for connection to a signal generator for monitoring or stimulating cardiac activity, and is constructed and arranged for implantation within a coronary vein. A portion of the distal portion of the lead body has a preformed radius of curvature substantially the same as or slightly smaller than a coronary sinus and geometrically shaped to hug a wall of the coronary sinus upon implantation therein. In addition, the lead further includes at least one electrode coupled with the lead body.
Several options for the lead are as follows. For example, the lead is constructed and arranged for implantation within the coronary sinus. In another option, the at least one electrode includes a first electrode associated with the distal portion of the lead body, and the first electrode includes a first electrode contact area. The at least one electrode further includes a second electrode associated with the distal portion of the lead body, and the second electrode includes a second electrode contact area. The distal portion of the lead is constructed and arranged to urge the first and second electrodes toward a wall of the coronary sinus. In yet a further option, the first electrode and the second electrode are spaced in close proximity to one another. Optionally, the lead further comprises at least one atrial pacing electrode. In yet another option, the distal portion of the lead body further includes a helical portion having the at least one electrode thereon, and the helical portion is constructed and arranged to urge the at least one electrode toward a myocardial wall. In a further option, the distal portion of the lead body further includes at least one arched tine located opposite the first electrode, and at least one arched tine located opposite the second electrode, where the tines are constructed and arranged to urge the electrode contact area of the first and second electrodes toward a myocardial wall of the coronary sinus. In another option, the distal portion of the lead body further comprises a double bias configuration constructed and arranged to urge the at least one electrode toward a myocardial wall of the coronary sinus. Other options include an external steroid collar disposed in close proximity to one electrode, or at least a portion of the lead body having a shape memory material. Still further, a distal portion of the lead body optionally has a tapered outer diameter.
In another embodiment, a lead is provided which includes a lead body adapted to carry signals to and from a heart, where the lead body has a proximal portion and a distal portion. The lead further includes a connector located at a proximal end of the lead. The lead is adapted for connection to a signal generator for monitoring or stimulating cardiac activity, and is constructed and arranged for implantation within a coronary vein. The distal portion of the lead body has a helical portion adapted to be implanted within a coronary vein. At least one electrode coupled with the helical portion of the lead body. Optionally, a plurality of electrodes are disposed on the helical portion, and the plurality of electrodes are spaced about 120 degrees apart along the helical portion.
Other optional features are as follows. For instance, the lead further includes apical electrodes, mid ventricular electrodes, and ventricular electrodes on the helical portion. In another example, at least a portion of the lead body comprises a shape memory material.
In yet another embodiment, a lead is provided which includes a lead body adapted to carry signals to and from a heart, where the lead body has a proximal portion and a distal portion, and an intermediate portion therebetween. The lead further includes a connector located at a proximal end of the lead. The lead is adapted for connection to a signal generator for monitoring or stimulating cardiac activity, and is constructed and arranged for implantation within a coronary vein. At least one electrode is coupled with the lead body. In addition, the distal portion of the lead body has a tapered outer diameter, and the outer diameter includes a first diameter at the intermediate portion and a second diameter at the distal portion, and the first diameter is greater than the second diameter.
Several options for the lead are as follows. For instance, the distal portion of the lead body further includes a helical portion which has the at least one electrode thereon, and the helical portion constructed and arranged to urge the at least one electrode toward a myocardial wall. As a further option, a plurality of electrodes are disposed on the helical portion, and the plurality of electrodes are spaced about 120 degrees apart along the helical portion. In yet another option, the lead further comprises apical electrodes, mid ventricular electrodes, and ventricular electrodes coupled with the lead body. Another example of an option is the distal portion of the lead body further includes at least one arched tine located opposite the at least one electrode. In yet another option, the at least one arched tine comprises a pliable, thin arched tine which extends from a first end to a second end, and the first end and the second end are coupled with the lead body.
A method for a cardiac vein lead is also described herein. The method includes providing any of the above coronary vein leads, inserting the coronary vein lead into the coronary sinus, advancing the lead from the coronary sinus toward the left atrium, and rotating the coronary vein lead. Optionally, the method further includes sensing and/or pacing the heart via the coronary vein lead.
In another method embodiment, a method includes providing any of the above coronary vein leads, where the coronary vein lead includes two or more electrodes, inserting the coronary vein lead into the coronary sinus, advancing the lead from the coronary sinus toward the left atrium. In one option, the method includes inserting a stylet into the coronary vein lead prior to inserting the coronary vein lead into the coronary sinus, and removing the stylet after inserting the coronary vein lead into the coronary sinus. In yet another option, the method further includes advancing the lead from the coronary sinus toward the left atrium and into a coronary branch vein. Another option includes pacing and sensing only the left atrium and/or the left ventricle.
In another method embodiment, a method includes providing any of the above coronary vein leads, where the coronary vein lead includes two or more electrodes, inserting the coronary vein lead into the coronary sinus, advancing the lead from the coronary sinus toward the left atrium. In one option, the method further includes placing a guide catheter into the coronary sinus, threading a guide wire into the coronary vein, and pushing the lead over the guide wire and into the coronary vein. In yet another option, the method further comprises hugging an interior wall of the coronary vein with the lead body.
In another method embodiment, a method includes providing any of the above coronary vein leads, where the coronary vein lead includes two or more electrodes, inserting the coronary vein lead into the coronary sinus, advancing the lead from the coronary sinus toward the left atrium. In one option, the method further comprises placing a guide catheter into the coronary sinus, threading a guide wire into the coronary sinus, pushing the coronary sinus lead over the guide wire and into the coronary sinus; and providing left sided sensing and pacing of the heart via the coronary sinus lead in its implanted site in the coronary sinus.
The leads advantageously provide the ability to sense and pace the heart using leads positioned within the cardiac vasculature, and further the leads provide the ability to pace and/or sense the left heart. It has been found that by placing a therapeutic lead near the atrium, but not in the atrium, higher amplitude electrograms may be detected as compared to a standard endocardial lead. Further, it has been found that left sided pacing may help suppress atrial arrhythmias, particularly those originating near the left atrium. Still further, it has been found that the ability to critically control the timing between pacing the atria and ventricles of the heart is of utility in optimizing pacing therapies. The leads described herein involve geometries that utilize the shape of the local vasculature, the shape of the heart, or both, to help insure that an optimally positioned lead will remain in that position well beyond the time of implant. The lead designs discussed herein yield reliable and optimal performance in sensing and pacing of the heart. New coronary lead configurations are provided which can provide dual chamber pacing and/or defibrillation on a single lead body.
These and other embodiments, aspects, advantages, and features of the present invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art by reference to the following description of the invention and referenced drawings or by practice of the invention. The aspects, advantages, and features of the invention are realized and attained by means of the instrumentalities, procedures, and combinations particularly pointed out in the appended claims and their equivalents.